The Fedora team has announced the Fedora 11 beta release. It comes packed with new features, such as Ext4 as the default filesystem, Nouveau driver by default, kernel mode setting on Intel, ATI and Nvidia drivers, many virtualization improvements, IBus input method, GCC 4.4, and much more.

I will trust the Ext4 developers assertions better than a random poster. If you have actual descriptions of problems, let me know. Rawhide kernel has all the patches that is going into 2.6.30. Linus has commented on Ext3 as well. No big deal. Again, if you don't have specific bug reports on actual issues, there is nothing much to do. Ext3 continues to remain as a option if you want to pick a conservative choice.